Merge pull request #120398 from aleksandra-malinowska/sts-restart-always

Make StatefulSet restart pods with phase Succeeded

pkg/controller/statefulset/stateful_set_control.go

@@ -375,13 +375,27 @@ func (ssc *defaultStatefulSetControl) processReplica(
 	replicas []*v1.Pod,
 	i int) (bool, error) {
 	logger := klog.FromContext(ctx)
-	// delete and recreate failed pods
+	// Delete and recreate pods which finished running.
+	//
+	// Note that pods with phase Succeeded will also trigger this event. This is
+	// because final pod phase of evicted or otherwise forcibly stopped pods
+	// (e.g. terminated on node reboot) is determined by the exit code of the
+	// container, not by the reason for pod termination. We should restart the pod
+	// regardless of the exit code.
+	if isFailed(replicas[i]) || isSucceeded(replicas[i]) {
 		if isFailed(replicas[i]) {
 			ssc.recorder.Eventf(set, v1.EventTypeWarning, "RecreatingFailedPod",
 				"StatefulSet %s/%s is recreating failed Pod %s",
 				set.Namespace,
 				set.Name,
 				replicas[i].Name)
+		} else {
+			ssc.recorder.Eventf(set, v1.EventTypeNormal, "RecreatingTerminatedPod",
+				"StatefulSet %s/%s is recreating terminated Pod %s",
+				set.Namespace,
+				set.Name,
+				replicas[i].Name)
+		}
 		if err := ssc.podControl.DeleteStatefulPod(set, replicas[i]); err != nil {
 			return true, err
 		}

pkg/controller/statefulset/stateful_set_control_test.go

@@ -170,6 +170,7 @@ func TestStatefulSetControl(t *testing.T) {
 		{ScalesDown, simpleSetFn},
 		{ReplacesPods, largeSetFn},
 		{RecreatesFailedPod, simpleSetFn},
+		{RecreatesSucceededPod, simpleSetFn},
 		{CreatePodFailure, simpleSetFn},
 		{UpdatePodFailure, simpleSetFn},
 		{UpdateSetStatusFailure, simpleSetFn},
@@ -435,6 +436,44 @@ func RecreatesFailedPod(t *testing.T, set *apps.StatefulSet, invariants invarian
 	}
 }
 
+func RecreatesSucceededPod(t *testing.T, set *apps.StatefulSet, invariants invariantFunc) {
+	client := fake.NewSimpleClientset()
+	om, _, ssc := setupController(client)
+	selector, err := metav1.LabelSelectorAsSelector(set.Spec.Selector)
+	if err != nil {
+		t.Error(err)
+	}
+	pods, err := om.podsLister.Pods(set.Namespace).List(selector)
+	if err != nil {
+		t.Error(err)
+	}
+	if _, err := ssc.UpdateStatefulSet(context.TODO(), set, pods); err != nil {
+		t.Errorf("Error updating StatefulSet %s", err)
+	}
+	if err := invariants(set, om); err != nil {
+		t.Error(err)
+	}
+	pods, err = om.podsLister.Pods(set.Namespace).List(selector)
+	if err != nil {
+		t.Error(err)
+	}
+	pods[0].Status.Phase = v1.PodSucceeded
+	_ = om.podsIndexer.Update(pods[0])
+	if _, err := ssc.UpdateStatefulSet(context.TODO(), set, pods); err != nil {
+		t.Errorf("Error updating StatefulSet %s", err)
+	}
+	if err := invariants(set, om); err != nil {
+		t.Error(err)
+	}
+	pods, err = om.podsLister.Pods(set.Namespace).List(selector)
+	if err != nil {
+		t.Error(err)
+	}
+	if isCreated(pods[0]) {
+		t.Error("StatefulSet did not recreate succeeded Pod")
+	}
+}
+
 func CreatePodFailure(t *testing.T, set *apps.StatefulSet, invariants invariantFunc) {
 	client := fake.NewSimpleClientset(set)
 	om, _, ssc := setupController(client)

pkg/controller/statefulset/stateful_set_utils.go

@@ -426,6 +426,11 @@ func isFailed(pod *v1.Pod) bool {
 	return pod.Status.Phase == v1.PodFailed
 }
 
+// isSucceeded returns true if pod has a Phase of PodSucceeded
+func isSucceeded(pod *v1.Pod) bool {
+	return pod.Status.Phase == v1.PodSucceeded
+}
+
 // isTerminating returns true if pod's DeletionTimestamp has been set
 func isTerminating(pod *v1.Pod) bool {
 	return pod.DeletionTimestamp != nil